feat(admin): export tool for full migration / backup (#5294)

* feat: export content utility (wip)

* feat: export navigation + groups + users

* feat: export comments + navigation + pages + pages history + settings

* feat: export assets

server/graph/schemas/system.graphql

@@ -17,7 +17,8 @@ extend type Mutation {
 type SystemQuery {
   flags: [SystemFlag] @auth(requires: ["manage:system"])
   info: SystemInfo
-  extensions: [SystemExtension]! @auth(requires: ["manage:system"])
+  extensions: [SystemExtension] @auth(requires: ["manage:system"])
+  exportStatus: SystemExportStatus @auth(requires: ["manage:system"])
 }
 
 # -----------------------------------------------
@@ -47,6 +48,11 @@ type SystemMutation {
   ): DefaultResponse @auth(requires: ["manage:system"])
 
   renewHTTPSCertificate: DefaultResponse @auth(requires: ["manage:system"])
+
+  export(
+    entities: [String]!
+    path: String!
+  ): DefaultResponse @auth(requires: ["manage:system"])
 }
 
 # -----------------------------------------------
@@ -121,3 +127,10 @@ type SystemExtension {
   isInstalled: Boolean!
   isCompatible: Boolean!
 }
+
+type SystemExportStatus {
+  status: String
+  progress: Int
+  message: String
+  startedAt: Date
+}